I've noticed that my iPhone 5 will hang on to a weak LTE signal right the way down to zero bars of signal displayed... this is great as whilst displaying zero bars of LTE I've had it speedtest at 17Mbps download and 15Mbps upload . Occasionally it will drop back onto 3G and get a full strong signal, but that's slower than the zero bars of LTE (or if I force it by disabling LTE in settings).

If I make a call when it's on the weak LTE signal it will automatically drop off LTE to get a better, more stable, signal. This too is good behaviour .

But if I try to send an SMS whilst on the weak LTE signal it'll just sit there failing to send. Retry after retry it will fail. I have to go into settings and disable LTE and then resend it. Then I'll also get a few SMS delivered to me that obviously weren't getting through when it was hanging onto the weak LTE signal.

Happened first thing again today. Was connected to weak LTE and an SMS failed to send. I then made a call which knocked it off of LTE, but it didn't get and retry sending automatically - I had to manually tell it to retry.

Quote:

Originally Posted by SellYourMacBook

have you tried doing a hard reset?

Hmm.
I've moved location since earlier, but interestingly doing a hard reset made the displayed signal meter jump from zero bars to two bars ... but speedtests at a rubbish 8Mpbs down and 2Mpbs up (this office really kills signal so that's expected). Anyways, just tried it and with the displayed two bars of LTE it did manage to send an SMS.

Will need to try it again back when I'm somewhere where it's stayed connected to LTE down at zero bars...

I know. That's why I find it annoying how the clever functionaility of "hang on to a weak LTE signal as it's still faster for data than the alternative strong 3G signal" breaks the functionaility of "send an SMS".

The two questions really are:

Why does a weak LTE signal manage to do 8/2Mpbs of data, but can't send an SMS?

Why does iOS come up with the SMS send failure message, but doesn't think to disconnect from the LTE and connect to the stronger 3G/EDGE/GPRS signal like it will to make a call and then retry sending?

I know. That's why I find it annoying how the clever functionaility of "hang on to a weak LTE signal as it's still faster for data than the alternative strong 3G signal" breaks the functionaility of "send an SMS".

The two questions really are:

Why does a weak LTE signal manage to do 8/2Mpbs of data, but can't send an SMS?

Why does iOS come up with the SMS send failure message, but doesn't think to disconnect from the LTE and connect to the stronger 3G/EDGE/GPRS signal like it will to make a call and then retry sending?

turn off celluar data, send a message. It's using the default 3G setting now, when you use LTE you switch to the LTE signal so if you have 1 bar of LTE of course it is going to take longer to send a text, it's not dependent on how fast the data upload is if that makes any sense, and because the LTE data upload is faster.